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Wind Sensors
#11
I have a question about the davis 6410
I am going to try to move my project over to an esp32. I have been looking over the davis circuit. Is there any reason why it wont run on 3.3 volts with shorter wire? I put 3.3 to it and seem to get values out but i need to wait a few days before my esp32 shows up.
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#12
I have a Question Smile I have a Davis 6410 wind sensor it is rated  for 5 volts I want to use ether a esp32 or esp8266 I have a SparkFun Logic Level Converter - Bi-Directional 5 to 3.3 volts It has spare channels that i am not using. Can i use this instead of a voltage divider for the wind direction pot. to the 3.3v analog pin. It would make the project smaller...

I would like to fit this device under my Anchor light the base is about 2.5 inches. It will have 3 sets of wire coming in. 12v to Anchor light out the top. 12 volt supply from wire up mast 2 pin connector and a 4 pin connector to Davis 6410 wind sensor.

I have plenty of pins to spare but i really don't need to know what the temperature or pressure is at the top of the mast. I could use it to add a running light and or a spot light, camera???



[Image: davis-wind-speed-direction.png]
Pin 2 Vin 5V  possible 3.3
Pin 3 Wind direction to analog rated 0 to 5 volts shift/divided to 3.3 to 0 output
pin 4 Ground
Pin 5 Wind speed rated 5v esp digital level 3.3 v
voltage drop on 40ft wire @ 3.3 to around 3 volts at pin less circuit above.
voltage drop on 40ft wire 24awg wire about .21 volts
The wire to the 6410 will be in the range of 2 ft this will result in .01 drop in voltage.

I have a few options..
1. Try to power the 6410 circuit by 3.3 V off the chip. power into chip via 9 V off the buck converter to Vin
  Advantages: easy , less parts
  Disadvantage: it will not work ???? or will it. The cable will have to be short due to voltage drop on the wire.

2. power the esp and 6410 circuit by 5 V off the buck converter and use the Logic Level Converter for the analog  circuit.
  Advantages: easy, 1 more part will work for the digital pins  I have extra pins on Logic Level Converter
  Disadvantage: it will may not work. can i use the level converter on a analog circuit.

3. power the 6410 circuit by 5 V off the buck converter and use voltage divider for the analog.Use Level Converter for the digital pin.
  Advantages: easy,  more parts will work
  Disadvantage: More parts.

I currently am using a nano with a Rfn24. I feed it 12 volts and draw off the 5V pin to feed the 6410 and 3.3 volts for the radio. my radio is 5 volt logic tolerant not all are.
 Advantage: No power supply all gpio are 5 volt, very low power. fast enough when working.
 Disadvantage: Need radio on RPI and extra code. Radios are a pain in the butt to get set just right. 32 byte max packet size, big enough for NMEA wind.  
 On the subject of price for a Davis when each part is bought separately they cost about $50 each out of china are heavy and bulky specs are questionable...
Balancing the Direction so it wont point down on heal.

I would consider making one but my 3d design and printing skills are poor. A pot for the direction works fine less short term reaction to wind and shaking of the boat. A low friction device works nice when it is level and not getting shaken.
The switch seems fine. It wont read low wind speeds but Why do i need to know there is no wind or not enough wind.

Oh Ya check out signalK sensors..
..
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#13
YEA:}
option 1 worked with the original wire length. Still sorting out code stuff.
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#14
I've been using the LCV Capteurs CV7 ultrasonic wind sensor with openplotter for a couple of years now. It's great. Walk around the marina and look up at how many wind sensors are not rotating or pointing in the correct direction. It outputs 0183 natively so just plug it into your USB adapter, no maintenance.
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#15
I assume you live in Europe? I was looking to see if they had a distributor in the US.

This is also interesting - this EBay vendor has a number of used ultrasonic sensors for cheap!
https://www.ebay.com/itm/Vaisala-WAS423A...Swfbhb0IyV
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#16
What is the power draw most of them i look at use a lot of power?
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#17
That's a good question! I looked it up - one of the production units I've been looking at is solar powered (https://calypsoinstruments.com/shop/prod...emometer-7), and they claim it will operate a very long time with no sunlight after a charge. As for the unit I was looking at on EBay, the manual says they require "10-15VDC at 29mA RMS".

Pretty darned good!
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#18
(2018-12-27, 02:15 PM)abarrow Wrote: That's a good question! I looked it up - one of the production units I've been looking at is solar powered (https://calypsoinstruments.com/shop/prod...emometer-7), and they claim it will operate a very long time with no sunlight after a charge. As for the unit I was looking at on EBay, the manual says they require "10-15VDC at 29mA RMS".

Pretty darned good!


What is a "very long time" ? In winter you might only get 6 hours daylight. Overcast the solar output is 20% if you are lucky. So at 29mA you are going to need a 6 watt solar panel up there to ensure it can operate all the time. How big is the solar panel?


I just tested today for the first time wind speed/direction sensors I printed on my 3d printer. It took me about 6 hours to print. This is really great because if something breaks off when you hit a tree, you can print that part again or you can print it larger to make it more sensitive.

It uses a magnet to measure wind angle, so very low friction, but I want to replace the stainless bearings with ceramic.

The cups have a magnet that fits in the printed hub to trigger a magnetic reed switch which is a proven method, and I see no real reason to change it.
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#19
Calypso claims "Autonomy with no sunlight: in sleep mode up to 1 year, while measuring up to ~30 days." That is of course with a decent charge. The 29 mA was for another sensor I was looking at on Ebay. That's still pretty low, but you are absolutely right that a little patch solar cell would be completely inadequate.

I don't know what microprocessor they use, but I do know that an ESP32 draws around 9 uA in sleep mode - it's considerably higher when Bluetooth is activated, so I doubt this is what they are using. According to the Calypso manual, the modes are determined by the state of the internal battery - below 20% it goes into "Low Power Mode" and only provides updates at 1HZ. Below 10% charge, it goes into sleep mode until recharged, only providing BLE advertisements. At 2.5% charge, it turns off until recharged.

I'm still on the fence about using wireless at all - I think regardless of their experience, getting a BLE signal from the masthead into the cabin is ambitious!

Can you take some photos of your new wind sensor? It sounds awesome.
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#20
(2018-12-26, 10:33 PM)abarrow Wrote: I assume you live in Europe? I was looking to see if they had a distributor in the US.

This is also interesting - this EBay vendor has a number of used ultrasonic sensors for cheap!
https://www.ebay.com/itm/Vaisala-WAS423A...Swfbhb0IyV

No, I live in the US.  I ordered from a European marine outfit, SVB I think.  At the time there were no US distributors and there still may not be any.  USD/Euro exchange is very good, shipping isn't too bad.
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